The present invention relates to a high-efficiency drying kiln, particularly for wood-like material, such as for example boards, panels, laths, et cetera.
It is known that a drying kiln for wood-like material comprises a supporting frame being covered with thermally insulated walls which delimit one or more chambers inside which the material to be dried is loaded. Such chambers are crossed by hot air which is propelled with a low head by blowers or fans.
A drawback of the drying kilns currently in use is that the blowers or fans being used generate a turbulent air flow which causes uneven velocity distribution of the air inside the kiln.
The nonuniformity of the air stream entails poor operation of the kiln, because the drying process does not occur evenly and uniformly on all the stacks of wood contained in the treatment chamber.
In particular, the drying of wood-like material can take even longer than a month, during which the kiln works uninterruptedly. Accordingly, it is evident why all the refinements aimed at reducing consumption and increasing the effectiveness of the heat exchange with the air can have a decisive effect on the total production costs of the products being treated.
The aim of the present invention is to provide a drying kiln in which the turbulences and nonuniformities of the distribution of the air that leaves the fans are reduced, so that each individual stack of wood-like material contained in the kiln is hit by the same amount of air, regardless of its position, in order to ensure a uniform and homogeneous drying process of the entire load of the kiln, thereby allowing to treat simultaneously rather large batches of stacks of wooden material.
Another object of the present invention is to provide a high-efficiency drying kiln which can operate with minimal consumption while maintaining a high heat exchange coefficient, in order to reduce the production costs related to the amount of fuel and electric power used per unit of treated material.
Another object of the present invention is to provide a drying kiln in which the hot air is changed and mixed continuously so as to achieve good recirculation on the material to be dried.
Not the least object of the present invention is to provide a drying kiln which can be manufactured easily and therefore has low manufacturing costs, so that its industrialization also is economically advantageous.
This aim and these and other objects which will become better apparent hereinafter are achieved by a high-efficiency drying kiln, particularly for wood-like material, which comprises:
at least one internal chamber, being covered with thermally insulating material and provided with at least one opening for loading and extracting a material to be treated,
at least two flues for recirculation of air inside said chamber by aspirating and delivering air respectively from and into the outside environment,
at least one air heating device,
at least one air acceleration duct, and
air acceleration means located inside said acceleration duct,
and characterized in that said air acceleration duct has, at least at an output section thereof, means for orienting in an axial direction an air stream that is forced by said acceleration means.
Conveniently, the air acceleration duct is arranged at the centerline and at the top of said internal chamber.
Advantageously, the kiln comprises an air channeling panel at least at an output end of the acceleration duct and externally thereto.